1. Field of the Invention
The present invention relates to calorstat support of heat engine having an external hot water circuit.
It is adapted to provide the necessary calories for the preheating of liquefied petroleum gas (LPG), or other fuel, used in particular for marine engines of all types, two- or four-stroke, carburetor or injection, outboard or inboard, but which can also be used for land engines or for other applications.
2. Discussion of Background Information
Liquefied petroleum gas is increasingly used as a source of energy for internal combustion engines. This fuel has the advantage of producing only very low pollution and is subject to a more advantageous taxation than that applied to other fuels.
Using liquefied gas to operate an engine initially designed to receive a liquid fuel requires a special device ensuring the vaporization of the gas under pressure and at a predetermined flow rate.
This device is in the form of a housing comprising a double enclosure formed of a chamber for vaporizing the gas, and of a thermal chamber in which a hot liquid circulates, which is generally constituted by the engine cooling water collected due to a branch provided on the circuit connecting the latter to the radiator.
The so-called water-cooled engines comprise an impervious closed circuit containing an aqueous solution containing anticorrosion additives and antifreeze. The cooling liquid is heated within the engine gearbox unit itself. It is then pumped to the upper portion of a water-air exchanger called the radiator and, after cooling, is returned to the engine. Its flow rate is controlled by a direct-action thermostat, i.e., a calorstat, located at the outlet of the engine gearbox unit, which shuts the circuit, when cold, in order to accelerate the heating of the liquid, at the start, until reaching its optimum temperature, and which then opens up to maintain this temperature constant.
The calorstat 1 is mounted on a support 2 attached to the engine gearbox unit 3 and communicating with the backflow pipe 4 of the water pump. It comprises a deformable bulb having a bellow and a spring 5, on the side of the pump, which controls the valve of an elementary cock (FIGS. 1 and 2). When cold, this cock is closed. When the engine starts to run, the temperature of the water for cooling the engine gearbox unit rises quickly, in the absence of any circulation. When the normal water temperature is reached, the cock opens up and initiates the water circulation in closed circuit, via the radiator. Thereafter, the opening is modified automatically as a function of the load of the engine and operating conditions of the radiator.
There are several known devices that use the engine cooling liquid to ensure the preheating of the liquefied petroleum gas. By way of example, Patent No. FR 2 757 217 describes a housing for vaporizing liquefied gas comprising, within the thermal chamber, a container or tubular circuit connected to the engine cooling water intake and outlet.
It takes a fairly a long time for the cooling liquid to reach the necessary temperature for vaporizing the liquefied gas, particularly in cold weather. Moreover, this temperature varies as a function of the engine speed.